Sound reproducer for phonographs



March 25, 1930. F. B. REED 1,752,201

SOUND REPRODUCER FOR PHONOGRAPHS Filed Aug. 27,-1928 Flam 1r 5. R123 INVENTOR WITNESSW ATTORNEY Patented Mar. 25, 1930 UNETED E FRANK B. REED, OF NEW BEDFORID, MASSACHUSETTS SOUND REPROD'UCER FOR PHONOGRAPHS Application filed August 27, 1928. Serial No. 302,224.

This invention relates to improvements in sound reproducers for phonographs.

The primary object of the invention is to provide a sound reproducer which embodies a pair of oppositely flexed diaphragms which may be adjusted to the desired degree of tension to suit the conditions of the phonegraph to which it is attached in order to areduce the maximum degree of tone qualities of the phonograph records over which it passes.

Another object of the invention resides in a phonograph reproducer which includes a flexible parchment diaphragm which may be adjusted to relieve any distortion which might be present during the playing of a phonograph record.

A further object is the provision of a phonograph reproducer in which the stylus bar is wholly supported from the vibrating diaphragm for imparting the maximum force of the sound impulses thereto.

With these and other objects in view, the invention resides in certain novel construction and combination and arrangement of parts, the essential features of which are hereinafter fully described are particularly pointed out in the appended claims, and are illustrated in the accompanying drawin in which Figure 1 is a perspective view of my improved sound reproducer.

Figure 2 is a vertical sectional View therethrough on the line 22 of Figure 1.

Figure 3 is a vertical sectional view on the line 33 of Figure 2.

Referring to the drawing by reference characters, the numeral 10 designates my improved sound reproducer for phonographs which includes a casing or housing 11 open at one side and having an attaching nipple or flange 12 extending from the opposite side by which the instrument may be fixedly attached to the tone arm of a phonograph in the usual manner. Fitting against the open side of the casing is a removable plate or disk 13 having an inwardly extending annular flange 1d. The plate is held in position by screws or the like 15, and is provided with a keyhole shape slot 16 therein for exposing certain working parts which will presently be described.

Fitting against the flange 14: are inner and outer diaphragms 17 and 18 constructed of flexible parchment glued together adjacent their peripheries and held against the flange by screws 19, the heads of which engage fibre or felt washers 20. F ixed to the axial center of the outer disk 18 as at 21 is one end of a stylus bar 22 which extends outward through the slot 16 and downwardly at an angle below the edge of the casing and terminates in a needle socket 23. The lower end of the stylus bar is braced by a bracket or arm 2% fixedly attached thereto and which bracket is also attached to the outer diaphragm 18. The usual phonograph needle 2% is received in the socket 23 and removably held therein by a clamping screw 25.

Bearing against the fixed connection 21 of the stylus bar is an adjustable tension screw 26 passing through the inner diaphragm 17 and threaded to a nutor boss 27 liked to the inner side of the diaphragn. By manipulating the screw to turn the same, the flex of the two diaphragms may be regulated to vary the tension of the same to suit the tone quality of the particular phonograph on which it is attached, in order to accurately reproduce the sound recorded on the record over which the needle 2% passes. The sound impulses from the stylus bar are, of course, directly transferred to the outer diaphragm and by reason of the adjusting screw 26 tightly engaging the fixed end of the stylus bar, impulses will also be transferred to the inner diaphragm 17. By mounting the stylus bar wholly upon the outer diaphragm and free of the casing, the full strength of the sound impulses is recorded.

A flat spring 28 is fixed to the inner dia phragm as shown in Figure 3 of the drawing and has its free end provided with a felt disk 29 which is pressed against the inner diaphragm to provide a cushion for absorbing any chatter of the diaphragm and to produce a soft natural tone.

T o adjust the flex of the diaphragms, it is only necessary to remove the screws 15 and remove the plate or disk 18', and after once adj usted to suit the condition, the plate may be replaced and the diaphragm left untouched until conditions change or the adjusting screw becomesloosened by the vibration of the diaphragms.

While I have described what I deem to be the most desirable embodiment of my invention, it is obvious that many of the details may be varied Without in any way departing from the spirit of my invention, and I therefore do not limit myself to the exact details of construction herein set forth nor to anything less than the whole of my invention limited only by the appended claims.

5 What is claimed as new is 1. A phonograph reproducer comprising a housing, a pair of flexible diaphragms mounted in said housing, a stylus bar fixedly attached to one of said diaphragms, and an adjustable screw threadedly carried by the other of said diaphragms and bearing against the fixed end of said stylus bar whereby turning of the screw will vary the flex of said diaphragms.

2. A phonograph reproducer comprising a housing open at one side, a removable plate fitting against the open side of said housing, a pair of flexible diaphragms fixedly carried by said plate, a stylus bar having one end "'0 fixedly connected to one of said diaphragms,

and an adjusting screw threadedly carried bythe other of said diaphragms and bearing against the fixed end of said stylus bar, sub stantially as and for the purpose specified.

3. A phonograph reproducer comprising a housing open at one side, a removable plate fitting against the open side of said housing, a pair of flexible diaphragms fixedly carried 7 by said plate, a stylus bar having one end 40 fixedly connected to one of said dianhragms, an adjusting screw threadedly carried by the other of said diaphragms and bearing against the fixed end of said'stylus bar, and a resilient cushion member mounted on said last mentioned diaphragm, substantially as and for the purpose specified.

i. In a phonograph reproducer having a diaphragm, a stylus bar wholly supported by said diaphragm and being provided with a .20 needle receiving socket at its freed end.

5. In a phonograph reproducer having a diaphragm, astylus bar having one end fixedly connected'to said diaphragm and provided with a needle receiving socket at its other end,

w and a bracket fixedly connected to said diaphragm and to said stylus bar.

In testimony whereof I have aflixed my signature.

FRANK B. REED. 

